Mercury
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SMALL WORLD
Mercury is the smallest planet in our solar system – only slightly larger than Earth's Moon.
ROUGH SURFACE
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Mercury is a rocky planet, also known as a terrestrial planet. Mercury has a solid, cratered surface, much like the Earth's moon.
RINGLESS
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There are no rings around Mercury.
Mercury is the closest planet to the Sun
The smallest planet in our solar system and nearest to the Sun, Mercury is only slightly larger than Earth's Moon.
From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as seven times brighter. Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system – that title belongs to nearby Venus, thanks to its dense atmosphere.
Because of Mercury's elliptical – egg-shaped – orbit, and sluggish rotation, the Sun appears to rise briefly, set, and rise again from some parts of the planet's surface. The same thing happens in reverse at sunset.
This series of oblique images highlight the wall and exterior of the beautiful volcanic vent located to the northeast of Rachmaninoff basin and west of Copland crater
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
10 Need-to-Know Things About Mercury
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INSIDE TRACK
Mercury is the planet that orbits the closest to the Sun.
FASTEST PLANET
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Mercury is the fastest planet in our solar system – traveling through space at nearly 29 miles (47 kilometers) per second. The closer a planet is to the Sun, the faster it travels. Since Mercury is the fastest planet and has the shortest distance to travel around the Sun, it has the shortest year of all the planets in our solar system – 88 days.
CAN'T BREATHE THERE
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Mercury's thin atmosphere, or exosphere, is composed mostly of oxygen (O2), sodium (Na), hydrogen (H2), helium (He), and potassium (K).
TOUGH PLACE FOR LIFE
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MOONLESS
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Mercury has no moons.
BIG SUN
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It is unlikely that life as we know it could survive on Mercury due to solar radiation, and extreme temperatures.
ROBOTIC VISITORS
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Standing on Mercury's surface at its closest approach to the Sun, our star would appear more than three times larger than it does on Earth.
Two NASA missions have explored Mercury: Mariner 10 was the first to fly by Mercury, and MESSENGER was the first to orbit. ESA's BepiColombo is on its way to Mercury.
Mercury in Pop Culture
The smallest planet in our solar system has a big presence in our collective imagination. Scores of science fiction writers have been inspired by Mercury, including Isaac Asimov, C. S. Lewis, Ray Bradbury, Arthur C. Clarke, and H. P. Lovecraft. Television and film writers, too, have found the planet an ideal location for storytelling. In the animated television show "Invader Zim," Mercury is turned into a prototype giant spaceship by the extinct Martians. And in the 2007 film "Sunshine," the Icarus II spacecraft goes into orbit around Mercury to rendezvous with the Icarus I.
In the comic strip "Calvin and Hobbes," Calvin and his classmate Susie give a presentation about Mercury, in which Calvin's contribution is full of questionable information: "The planet Mercury was named after a Roman god with winged feet," says Calvin. "Mercury was the god of flowers and bouquets, which is why today he is a registered trademark of FTD florists. Why they named a planet after this guy, I can't imagine."
